计算器C++，实现加减乘除，有MFC界面-Cal

C++ MFC是C++编程界面设计很重要的一个方面，本文档通过一个简单的案例 简易计算器，来说明C++ MFC的具体实现过程，简单明了，非常适合初学者。-C++ MFC is C++ programming interface design is very important aspect, the present document by a simple case- a simple calculator to illustrate the implementation process C++